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performance: get rid of repeated dereferencing of use_iterator by caching its result

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git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@100547 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Gabor Greif
2010-04-06 19:14:05 +00:00
parent 0b520db74d
commit a01d6db569
1 changed files with 28 additions and 21 deletions
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43
lib/Transforms/IPO/GlobalOpt.cpp
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@ -612,40 +612,44 @@ static GlobalVariable *SRAGlobal(GlobalVariable *GV, const TargetData &TD) {
/// phi nodes we've seen to avoid reprocessing them. /// phi nodes we've seen to avoid reprocessing them.
static bool AllUsesOfValueWillTrapIfNull(Value *V, static bool AllUsesOfValueWillTrapIfNull(Value *V,
SmallPtrSet<PHINode*, 8> &PHIs) { SmallPtrSet<PHINode*, 8> &PHIs) {
for (Value::use_iterator UI = V->use_begin(), E = V->use_end(); UI != E; ++UI) for (Value::use_iterator UI = V->use_begin(), E = V->use_end(); UI != E;
if (isa<LoadInst>(*UI)) { ++UI) {
User *U = *UI;
if (isa<LoadInst>(U)) {
// Will trap. // Will trap.
} else if (StoreInst *SI = dyn_cast<StoreInst>(*UI)) { } else if (StoreInst *SI = dyn_cast<StoreInst>(U)) {
if (SI->getOperand(0) == V) { if (SI->getOperand(0) == V) {
//cerr << "NONTRAPPING USE: " << **UI; //cerr << "NONTRAPPING USE: " << *U;
return false; // Storing the value. return false; // Storing the value.
} }
} else if (CallInst *CI = dyn_cast<CallInst>(*UI)) { } else if (CallInst *CI = dyn_cast<CallInst>(U)) {
if (CI->getCalledValue() != V) { if (CI->getCalledValue() != V) {
//cerr << "NONTRAPPING USE: " << **UI; //cerr << "NONTRAPPING USE: " << *U;
return false; // Not calling the ptr return false; // Not calling the ptr
} }
} else if (InvokeInst *II = dyn_cast<InvokeInst>(*UI)) { } else if (InvokeInst *II = dyn_cast<InvokeInst>(U)) {
if (II->getCalledValue() != V) { if (II->getCalledValue() != V) {
//cerr << "NONTRAPPING USE: " << **UI; //cerr << "NONTRAPPING USE: " << *U;
return false; // Not calling the ptr return false; // Not calling the ptr
} }
} else if (BitCastInst *CI = dyn_cast<BitCastInst>(*UI)) { } else if (BitCastInst *CI = dyn_cast<BitCastInst>(U)) {
if (!AllUsesOfValueWillTrapIfNull(CI, PHIs)) return false; if (!AllUsesOfValueWillTrapIfNull(CI, PHIs)) return false;
} else if (GetElementPtrInst *GEPI = dyn_cast<GetElementPtrInst>(*UI)) { } else if (GetElementPtrInst *GEPI = dyn_cast<GetElementPtrInst>(U)) {
if (!AllUsesOfValueWillTrapIfNull(GEPI, PHIs)) return false; if (!AllUsesOfValueWillTrapIfNull(GEPI, PHIs)) return false;
} else if (PHINode *PN = dyn_cast<PHINode>(*UI)) { } else if (PHINode *PN = dyn_cast<PHINode>(U)) {
// If we've already seen this phi node, ignore it, it has already been // If we've already seen this phi node, ignore it, it has already been
// checked. // checked.
if (PHIs.insert(PN) && !AllUsesOfValueWillTrapIfNull(PN, PHIs)) if (PHIs.insert(PN) && !AllUsesOfValueWillTrapIfNull(PN, PHIs))
return false; return false;
} else if (isa<ICmpInst>(*UI) && } else if (isa<ICmpInst>(U) &&
isa<ConstantPointerNull>(UI->getOperand(1))) { isa<ConstantPointerNull>(UI->getOperand(1))) {
// Ignore icmp X, null // Ignore icmp X, null
} else { } else {
//cerr << "NONTRAPPING USE: " << **UI; //cerr << "NONTRAPPING USE: " << *U;
return false; return false;
} }
}
return true; return true;
} }
@ -653,19 +657,22 @@ static bool AllUsesOfValueWillTrapIfNull(Value *V,
/// from GV will trap if the loaded value is null. Note that this also permits /// from GV will trap if the loaded value is null. Note that this also permits
/// comparisons of the loaded value against null, as a special case. /// comparisons of the loaded value against null, as a special case.
static bool AllUsesOfLoadedValueWillTrapIfNull(GlobalVariable *GV) { static bool AllUsesOfLoadedValueWillTrapIfNull(GlobalVariable *GV) {
for (Value::use_iterator UI = GV->use_begin(), E = GV->use_end(); UI!=E; ++UI) for (Value::use_iterator UI = GV->use_begin(), E = GV->use_end();
if (LoadInst *LI = dyn_cast<LoadInst>(*UI)) { UI != E; ++UI) {
User *U = *UI;
if (LoadInst *LI = dyn_cast<LoadInst>(U)) {
SmallPtrSet<PHINode*, 8> PHIs; SmallPtrSet<PHINode*, 8> PHIs;
if (!AllUsesOfValueWillTrapIfNull(LI, PHIs)) if (!AllUsesOfValueWillTrapIfNull(LI, PHIs))
return false; return false;
} else if (isa<StoreInst>(*UI)) { } else if (isa<StoreInst>(U)) {
// Ignore stores to the global. // Ignore stores to the global.
} else { } else {
// We don't know or understand this user, bail out. // We don't know or understand this user, bail out.
//cerr << "UNKNOWN USER OF GLOBAL!: " << **UI; //cerr << "UNKNOWN USER OF GLOBAL!: " << *U;
return false; return false;
} }
}
return true; return true;
} }